The present invention relates to a method of joining two members of a vehicle seat, with a first of the members having a projection and the second of the members having a receptacle, and the two members being joined by inserting the projection into the receptacle and then welding.
For a known method of the above-described kind, for example, the upper member of a hinge fitting includes two projecting facets in the form of triangular, truncated pyramids, which are inserted into receptacles of an adaptation member of the seat back structure. The upper member and the adaptation member are then joined by electric welding. A disadvantage of this known method is that weld spatters may form, which adversely affects the function of the hinge fitting, so that it must be eliminated as a reject.
In accordance with one aspect, the present invention solves the above and other problems by the provision of improvements to the above-described method, by way of which damage to sensitive parts of a vehicle seat is avoided. In accordance with this aspect, a method of joining two members of a vehicle seat includes providing a first member with at least one projection, providing a second member with at least one bore that extends through the second member, and then joining the members. The members are joined by inserting the projection into the bore, and then welding the first and second members together by forming a weld inside the bore while the projection is within the bore. The welding is effected from a side of the second member facing away from the first member. More specifically, the welding is preferably effected by introducing a welding medium, such as a laser beam, into the bore from the side of the second member facing away from the first member.
As a result of performing the welding on the side of the second member facing away from the first member, and forming the weld inside a receptacle, which is designed and constructed as the above-mentioned through bore, the risk of weld spatters on the outer side of the parts is lessened, in particular where sensitive components are located. For purposes of substantially avoiding weld spatters, welding occurs preferably within the receptacle, in a location set back from the side facing away from the first member. By inserting a projection into the receptacle, a preliminary positioning occurs, which does not require additional auxiliary means. In addition, forces can be adequately transmitted without requiring that the weld seam include large quantities of material.
To provide a reliable cohesion, it is preferred for the weld seam to be positioned inside the receptacle and surround the projection. To obtain an accurately positioned weld seam, it is of advantage to form a channel in which the weld seam is formed inside the receptacle. For example, the channel can be formed by means of bevels, radii, or the like on the projection and/or on the receptacle on the side facing away from the first member and set back from the latter. Preferably, the two members are joined by means of laser welding. This kind of welding exhibits especially little distortion. However, other kinds of welding are also possible. It is possible to accomplish an initial centering, and with that likewise an accurate positioning of the weld seam, in that the projection and the receptacle are provided with the same, for example, circular cross section and little play, and no play if possible. Likewise possible are other cross sections, for example, triangular.